Jul. 11, 2012

Today while we were teaching, we threw out a fact that entomologists use all the time to “wow” people: House flies can beat their wings 200 times per second. Michael Barton of Exploring Portland’s Natural Areas asked us, “How does that compare to a hummingbird?” We had no idea.

So for this post, we did a little research so we could talk about amazing insect feats in relation to animals people are more familiar with.

Flying

A house fly can beat its wings 200 times per second, while most hummingbirds average 90 wingbeats/sec. However, we did find that during courtship the ruby-throated hummingbird beats its wings 200 times per second. So does this mean that some hummingbirds can beat their wings as fast as flies? Nope – there’s a species of midge (a type of tiny fly) that can beat its wings 1,046 times/sec!

We could go into the “how”, but we could be writing on the physio-morphology of insect flight for days. So we’ll ask the question that we’re always asked as teachers: Why do they beat their wings so fast? It’s because the smaller you are and the smaller your wings, the more difficult it is to move the air around you. To insects, air is thick and syrupy. Many scientists have said that for flies, flight is like swimming through molasses. The insects that flap their wings the fastest can do maneuvers in the air like hovering, zipping side to side, and even flying backwards. It’s no coincidence then that the bird that flaps its wings the fastest can also pull off these fancy flight moves!

Everyone talks about how cockroaches run so fast, but when compared to, say, a galloping horse – for their size, are they really so fast? Yes! American cockroaches have been clocked at a top speed of 50 body lengths per second. A fast thoroughbred can run about 58.3ft/sec. But if a horse were able to run like a cockroach it would run 450 ft/sec based on its body length. There are many reasons they can’t do that. Weight is a big factor, as is the stability of their gate. Cockroaches run in a tripod gait – at any one time they have three legs on the ground. Horses have anywhere between zero and two legs on the ground during a full gallop.

Fleas can jump over 150 times their own body length. They’re tiny insects, so this may not seem like a big jump. But let’s put it into human terms. Kristie is 5’9” tall (69 inches). If Kristie could jump like a flea, she’d be able to jump 862.5 feet into the air. This means she could leap over the Washington Monument and clear it by 307 ft.

In this excerpt from our video about the Order Siphonaptera (fleas), we talk about a substance in their bodies that helps them jump, the largest flea, and the recent discovery of flea fossils in China. To learn more about Jurassic fleas, read more about the collaboration between Chinese, French, and American scientists here.